If you want to know the launch environment of your client application, simply ask the launcher. A launcher is always related to a specific environment, e.g., web/html, mobile, or desktop.

If your application should behave or look different in different environments, simply check the environment via:

<launcher>.getEnvironmentName();

This command returns DESKTOP if you are using SwingApplication or SwingApplet as launcher. There's no difference if your application runs as webstart, mobile, or desktop application. Swing is always Desktop environment.

There are some useful constants in ILauncher:

ENVIRONMENT_DESKTOP, 
ENVIRONMENT_WEB,
ENVIRONMENT_MOBILE,
ENVIRONMENT_HEADLESS

A simple way to check the environment is available via UILauncher, e.g.

<uilauncher>.isDesktopEnvironment();

Attention

If you use JVx' DBSecurityManager, be aware that it checks ENV_ columns. If your WORKSCREENS table contains the column ENV_DESKTOP (values: Y, N), the security manager ignores all screens that don't fit your client environment. It's very easy to configure one screen for different environments without changing role assignments.